Custom CNC Machined Aluminum Mounting Flanges

FlexiTurn provides precision CNC machining services for custom aluminum mounting flanges, exemplified by the square interface flange shown above. This part features a central through bore, a four-hole bolt circle with counterbores, edge relief slots, and a precision mounting face. Every dimension and geometric tolerance is defined by your 2D or 3D CAD data. FlexiTurn is a CNC machining service provider — the part you receive is machined to your drawing.

Machining Capabilities Demonstrated by This Flange

Aluminum mounting flanges appear simple until two functional requirements collide: the bore that carries the bearing, sensor, or shaft, and the mounting face that sits flat against the machine frame. If these features are machined without a unified datum, bolt tightening distorts the bore and introduces misalignment. FlexiTurn addresses this with the following process controls:

• CNC Milling & Turning: The square outer profile and relief slots are milled, while the central bore is turned or precision-bored to maintain roundness and size.
• Counterbore & Bolt Hole Accuracy: Four mounting holes are drilled and counterbored with controlled depth to ensure fastener heads sit flush without interfering with mating components.
• Datum-Aligned Machining: Where geometry permits, the bore, mounting face, and bolt hole pattern are machined referencing a common datum, minimizing cumulative error between the locating feature and the fastening features.
• 3/4/5-Axis Capability: For flanges with angled ports, stepped faces, or multi-sided features, multi-axis machining reduces re-fixturing and preserves positional relationships.

Material Selection

FlexiTurn machines aluminum mounting flanges from the alloys most commonly specified for structural and interface applications:

• 6061-T6: Good machinability, moderate strength, and consistent anodizing response. Suitable for general equipment mounting, sensor bases, and automation frames.
• 7075-T6: Higher strength-to-weight ratio than 6061. Suitable for load-bearing brackets, servo motor mounts, and weight-sensitive assemblies.

Both grades are sourced from certified suppliers with documented mill test reports.

Tolerances & Quality

Typical machining tolerances for aluminum mounting flanges:

• General tolerances: ISO 2768-m (or ±0.05 mm typical)
• Critical bores and mating faces: ±0.01 mm to ±0.005 mm upon engineering review
• Flatness (mounting face): ≤0.02 mm
• True Position (bolt hole pattern relative to bore): ≤0.02 mm
• Surface roughness: Ra 1.6–3.2 μm as-machined; finer available with additional finishing

FlexiTurn performs in-process dimensional verification and final inspection on critical features. CMM reports and material certificates are available upon request. The quality management system is ISO 9001:2015 certified.

Surface Finishing

Bare aluminum is not suitable for long-term service. FlexiTurn coordinates finishing matched to your environment:

• Anodizing (Type II or Type III): Black, clear, or custom colors for corrosion resistance and wear resistance.
• Bead Blasting / Sandblasting: Uniform matte finish and reduced glare.
• Chromate Conversion Coating: Conductive alternative where anodizing is not permitted.

Note: Threaded holes and precision bores are masked or dimensionally compensated before coating to preserve final fit.

Why Choose FlexiTurn

FlexiTurn is a China-based precision CNC machining service provider focused on custom engineered components.

Flange machining focus: We understand the interaction between bore position, mounting-face flatness, and bolt-circle accuracy — and control them through setup and datum strategy.

Multi-axis capability: 3-axis, 4-axis, and 5-axis milling and turning for complex flange geometries.

DFM review before production: We check feature accessibility, wall thickness, and tolerance stack-up before quoting.

No tooling cost: CNC machining eliminates mold or die investment for prototypes and low-to-medium volume builds.

Documented traceability: Certified raw materials and inspection reports with every production order.

FlexiTurn serves industries including automation machinery, industrial equipment, robotics, optical systems, and medical device subassemblies.

Get Started

Submit your 2D/3D CAD files, specify the aluminum grade (6061-T6 or 7075-T6), critical tolerances, and surface finish requirement. FlexiTurn’s engineering team will review your flange design, provide DFM feedback, and deliver a detailed quotation.

Contact FlexiTurn today to discuss your aluminum mounting flange machining requirements.

FlexiTurn – Precision Machining, Delivered with Trust.